A conductive adhesive, which is an adhesive having both electrical conductivity and bonding performance, can connect various conductive materials or conductive elements together so as to form conductive paths between the connected conductive materials or conductive elements. A conductive adhesive is widely used in the field of manufacturing electronic devices. A conductive adhesive is usually composed of two parts, that is, a mainbody glue material having a binding property and a conductive filler.
In the conductive adhesive, the conductive filler mainly comprises three major categories of materials, i.e., metal oxides, metals, carbon-based materials. Since metal oxides generally have poor electrical conductivity, metals or carbon-based materials are usually used as the conductive filler. Metallic conductive fillers are usually particles of a metal having a relatively low electrical resistivity selected from Au (gold), Ag (silver), Cu (copper), Ni (nickel), etc. Due to having excellent electrical conductivity and chemical stability, Au or Ag particles are more suitable for the conductive adhesive as the conductive fillers than Cu and Ni particles. However, due to high price, use of Au or Ag will cause a sharp increase in the cost of the manufacture of electronic devices, which is not good for large-scale production. The carbon-based materials such as carbon black also have good electrical conductivity and a relatively low price, and thus use of the carbon-based materials can achieve a cheap conductive adhesive and large-scale production.
However, it is very difficult to homogeneously fine carbon-based materials and well disperse them in a mainbody glue material. Therefore, there is a problem that processing is difficult with use of the carbon-based material as the conductive filler in the conductive adhesive. Moreover, the electrical conductivity of the carbon-based material varies greatly with producing areas of raw materials and other factors, and processing repeatability of them is poor.